I went down to my boat and made a cardboard template to have a stainless plate made. I'd like to be able to do your glass job Sandpiper, it's just that "Noone could tell the difference." is about the furthest thing from the reaction I've ever gotten to any of my crude fiberglass repair attempts.
I looked at mine and was a little discouraged about the prospect of detaching the forestay AND the chainplate, and completely extracting the whole old piece.
I thought of a slightly different idea. I'm going to make a stainless piece exactly like the old one that sits right on top of the old one, with a rectangular slot cut out for the deck side part of the chainplate, so the only thing I will have to unbolt are my port and starboard bow cleats. They have bolts plenty long enough to accommodate the thickness of another piece, and will hold the new piece firmly in place when re-installed. I will have it made with a 90 degree 1 1/2 " lip overhanging the edge, which will cover all the damage and sealing up I will do.
Here's a photo of the ugliness as it is, and the template I made. I had some black nylon chocks laying around for years that I could never attach to the old plate because there wasn't enough room between my cleats and the edge of the hull to drill and through bolt them, I'm going to screw them on to the new plate where they are in the second photo of my template. I'll update as I go.